The CDC and NIAID have classified Ebola virus (EBOV) and Marburg virus (MARV) as Category A priority pathogens. EBOV and MARV cause severe and often fatal hemorrhagic fever in humans and nonhuman primates with case fatality rates up to 90% for some species or strains such as EBOV Zaire and MARV strain Angola. There are presently no approved active or passive therapeutic modalities for EBOV infections resulting from a natural outbreak, laboratory accident, or deliberate misuse. Therefore, identification of effective small molecule inhibitors of filoviral IFN-antagonists and of VP30 function that can be developed into drugs would be of high significance. The goal of this Center Is to develop small molecule anti-filoviral therapeutics that target filoviralinterferon (IFN) antagonist functions and VP30 function. Fundamental to this effort will be the testing of candidate compounds for antiviral activity against EBOV and MARV in cell culture and in animal models. Such testing must be performed at Biosafety Level 4 / Animal Biosafety level 4 (BSL- 4/ABSL-4) in accordance with SelectAgent rules. The BSL4 core will first evaluate the antiviral activity of compounds identified by Projects 2 and 3 in cell culture. Lead inhibitors will be further evaluated in the mouse and guinea pig models of EBOV or MARV Infections to identify the best preclinical development candidates. Therefore, Core B will provide the proof of concept for the antiviral activities of hit compounds isolated In Projects 2 and 3. Moreover, Core B has an important role in the hit to lead optimization. Its efforts together with the efforts from Projects 1, 2 and 3 will provide the relationships between analog structure and four key features - anti-filovirus activity, In vitro ADME including potential oral bioavailability, in vivo efficacy and safety. Further, an understanding of the MOA, as outlined in Projects 1 and 3, will be very Important In the design and future development of these first-in-class inhibitors by, for example, alleviating concerns about target-based toxicity.